Integrated freestanding single-crystal silicon nanowires: conductivity and surface treatment

Because of the large surface-to-volume ratio, the conductivity of semiconductor nanostructures is very sensitive to surface chemical and structural conditions. Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the surface, are compared. The sheet resistance of the SiNMs, measured by the van der Pauw method, shows that HF etching produces at least an order of magnitude larger drop in sheet resistance than that caused by VH treatment, relative to the very high sheet resistance of samples terminated with native oxide. Re-oxidation rates after these treatments also differ. X-ray photoelectron spectroscopy measurements are consistent with the electrical-conductivity results. We pinpoint the likely cause of the differences.PACS: 73.63.-b, 62.23.Kn, 73.40.Ty

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“…It is well known that HF etching of the oxide leaves a nominally H-terminated Si(001)surface, but with some residual F [12,13]. …”

Section: Introductionmentioning

confidence: 99%

Influence of surface properties on the electrical conductivity of silicon nanomembranes

et al. 2011

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“…Of course, in a thin-sheet geometry, one always has two interfaces. These can be made nominally identical for a free-standing NM 9 , but in practice the simpler and more relevant situation involves the nanomembrane resting on a host substrate, with an intervening dielectric layer. This dielectric layer allows use of the host substrate as a control gate.…”

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confidence: 99%

Probing the electronic structure at semiconductor surfaces using charge transport in nanomembranes

et al. 2013

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The electrical properties of nanostructures are extremely sensitive to their surface condition. In very thin two-dimensional crystalline-semiconductor sheets, termed nanomembranes, the influence of the bulk is diminished, and the electrical conductance becomes exquisitely responsive to the structure of the surface and the type and density of defects there. Its understanding therefore requires a precise knowledge of the surface condition. Here we report measurements, using nanomembranes, that demonstrate direct charge transport through the p* band of the clean reconstructed Si(001) surface. We determine the charge carrier mobility in this band. These measurements, performed in ultra-high vacuum to create a truly clean surface, lay the foundation for a quantitative understanding of the role of extended or localized surface states, created by surface structure, defects or adsorbed atoms/molecules, in modifying charge transport through semiconductor nanostructures.

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“…The electrodes and the RTD are made of a 25 nm thick nickel film. The device is fabricated with a standard micromachining technique, and the detailed fabrication method is described elsewhere 43–46 . In brief, the inlet, outlet, and channel are formed by 30% w/w KOH etch at 60 °C bath temperature.…”

Section: Methodsmentioning

confidence: 99%

Localized Dielectric Loss Heating in Dielectrophoresis Devices

Kwak

Hossen

Bashir

et al. 2019

Sci Rep

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Temperature increases during dielectrophoresis (DEP) can affect the response of biological entities, and ignoring the effect can result in misleading analysis. The heating mechanism of a DEP device is typically considered to be the result of Joule heating and is overlooked without an appropriate analysis. Our experiment and analysis indicate that the heating mechanism is due to the dielectric loss (Debye relaxation). A temperature increase between interdigitated electrodes (IDEs) has been measured with an integrated micro temperature sensor between IDEs to be as high as 70 °C at 1.5 MHz with a 30 Vpp applied voltage to our ultra-low thermal mass DEP device. Analytical and numerical analysis of the power dissipation due to the dielectric loss are in good agreement with the experiment data.

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Integrated freestanding single-crystal silicon nanowires: conductivity and surface treatment

Cited by 11 publications

References 42 publications

Influence of surface properties on the electrical conductivity of silicon nanomembranes

Influence of surface properties on the electrical conductivity of silicon nanomembranes

Probing the electronic structure at semiconductor surfaces using charge transport in nanomembranes

Localized Dielectric Loss Heating in Dielectrophoresis Devices

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